Air intake conduitry for a motorcycle

ABSTRACT

A motorcycle includes a frame that mounts on engine and a fuel tank. The fuel tank is mounted above the engine. Air intake conduitry includes an upwardly extending intake pipe, an upwardly extending connecting pipe, and a connecting box immediately beneath the fuel tank, atop the intake and connecting pipers, which serves to connect them so as to provide an air intake conduit from the atmosphere to the engine. In a V-type engine, the pipes and box are disposed in the angle between the cylinders. In multi-bank engines, which utilize a pair of intake pipes, the connecting pipe, and also an air cleaner, can be disposed between them. When the fuel tank includes a pair of draped sides to form a saddle-like tank, the connecting box can be disposed between the draped sides.

FIELD OF THE INVENTION

This invention relates to air intake conduitry for motorcycles, andespecially to compact conduitry which can efficiently utilize the spaceabove the motorcycle engine and immediately underneath the fuel tank.

BACKGROUND OF THE INVENTION

Conventionally, a motorcycle is provided with an intake pipe whichextends rearwardly from the engine, and an air cleaner or like devicesdisposed beneath the rider's seat. This arrangement inevitably increasesthe length of the pipe of intake system, resulting in an increased firstand last length of engine. In order to obviate this shortcoming of theprior art, it has been proposed to extend the intake pipe upwardlydirectly from the engine. In such a case, the air cleaner must bedisposed under or between the draping sides of the fuel tank, which inturn reduces the capacity or volume of the fuel tank. Particularly inthe case of a motorcycle having a V-type engine, the piping arrangementof intake and exhaust systems are inconveniently complicated. This givesrise to the demand for air intake conduitry with a simple and compactarrangement of its pipes.

BRIEF DESCRIPTION OF THE INVENTION

According to the invention, there is provided an air intake conduitryhaving an intake pipe extending upwardly from an engine, a connectingpipe disposed in the vicinity of the intake pipe, and a connecting boxthrough which the upper end opening of the connecting pipe is connectedto the upper end opening of the intake pipe, the connecting box beingdisposed immediately beneath the fuel tank. This arrangement permitsreduction of the first and last length of the engine without reducingthe capacity of the fuel tank, the reduction of length reducing theengine space and reduction the wheel base. The piping arrangement iseffective to make motorcycle simplified and rendered compact.

According to a preferred but optional feature of the invention, an aircleaner can be connected to the lower end of the connecting pipe. In amultiple-bank engine, it can be disposed between the banks.

The above and other features of the invention will be fully understoodfrom the following detailed description and the accompanying drawings,in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partly-sectioned side elevational view of a motorcycleincorporating the invention; and

FIG. 2 is an enlarged sectional view of a portion of the motorcycleshown in FIG. 1.

DETAILED DESCRIPTION OF THR DRAWINGS

Referring first to FIG. 1, a frame 1 and a steering head pipe 2 of amotorcycle are shown. The motorcycle is further provided with a pair(right and left sides) of tank rails 3 and also a pair (right and leftsides) of side tubes 4. A front fork 5 is rotatably held to the frame bythe head pipe 2. The front and rear wheels are designated by referencenumerals 6 and 7, respectively. The rear wheel 7 is held by a rear arm 8which is pivotally secured to the main frame 1 for free verticalswinging movement.

A V-type engine 9 having banks 10, 11 which are respectively inclined tothe front and rear is disposed between the side tubes 4. Engine 9 ismounted with its right and left sides suspended from the side tube 4.

Multi-bank Engine 9 has intake pipes 12 disposed at the inner sides ofthe banks 10, 11 of cylinders. Pipes 12 extend upwardly andsubstantially vertically. Exhaust pipes 13, 14 are connected to theouter sides of the banks 10,11. More specifically, exhaust pipe 13projects forwardly from the engine 9 and then bends to extend beneathengine 9 to be connected to an exhaust silencer box 15. The otherexhaust 14 extends rearwardly from engine 9 and through the spacebetween the rear wheel 7 and the pivot shaft 16 of the aforementionedrear arm 8 to be connected to the silencer box 15. A silencer pipe ormuffler 17 for releasing the exhaust gas rearwardly is connected tosilencer box 15.

A radiator 18 is provided for cooling the cooling water circulated inthe engine 9. The radiator 9 is mounted to side tubes 4.

A fuel tank 19 is installed to bridge both tank rails 3. It has drapedsides, rather like a saddle, to form a bottom generally shaped as aninverted "U". Intake pipes 12 extend at their upper ends immediatelybeneath the fuel tank, between the draped sides, i.e., within the sideboundaries of the tank, but of course not inside the wall of the tankwhere the fuel is, although fuel is contained in the draped sides oneither side. As shown in FIG. 2, the intake pipes 12 have upper endswhich open into the inside of a connecting box 20 disposed at a positionwhich is between the draped sides of the fuel tank 19, and between thepair of tank rails 3. A connecting pipe 21 extends downwardly from theconnecting box 20. Connecting pipe 21 is substantially parallel to theintake pipes 12 in the space between them. An air cleaner 22 is attachedto the lower end of the connecting pipe 21.

Intake pipes 12 are provided with carburetors which are known per se.The carburetors have throttle valves 23 adapted to be operated to changethe engine output. A rider's seat 24 is shown just behind the fuel tank.

In the embodiment having the described construction, ambient air issucked into and through the air cleaner 22 and the connecting pipe 21,and thence through intake pipes 12 to the engine.

It will be seen that in the described embodiment, applied to a V-typeengine, it is possible to arrange conduitry of the intake system inquite a simple and compact manner by efficient use of the space betweenthe banks 10,11 of engine 9. According to this embodiment, theconnecting box 20 can also play the role of an intake silencer, becauseit has a volume sufficiently large to absorb the pulsation of the intakeflow for each cylinder. The level of the intake noise is loweredconsiderably.

Although the invention has thus far been described with specificreference to a V-type engine, this is not the exclusive application. Theinvention can also be applied to any other type of engine which isconstructed to permit the vertical arrangement of an intake pipe orpipes from the engine up to the underside of the fuel tank, oftenbetween its draped sides.

As has been described, according to the invention, there is provided anintake system for motorcycles comprising an intake pipe or pipesextending upwardly from the engine, a connecting pipe disposedsubstantially vertically in the vicinity of the intake pipe or pipes, anair cleaner attached to the lower end of the connecting pipe and aconnecting box through which the upper end opening of the connectingpipe is connected to the upper opening or openings of the intake pipe orpipes, the connecting box being disposed at the under side of the fueltank. According to this arrangement, there is no substantial decrease ofthe capacity of fuel tank, because it is not necessary to install an aircleaner adjacent to the fuel tank. In addition, the reduced length ofthe pipes of the intake system offers the advantages of increased engineoutput due to reduced intake resistance, and a simplified and compactarrangement of pipes of the intake system.

This invention is not to be limited by the embodiment shown in thedrawings and described in the description, but only in accordance withthe scope of the appended claims.

I claim:
 1. In combination:a motorcycle frame; a multi-bank,multi-cylinder V-type engine supported by said frame; a fuel tanksupported by said frame, said fuel tank being disposed above said engineand being generally V-shaped, with legs depending downwardly at eachside; and air intake conduitry comprising a respective air intake pipeextending upwardly from each bank of said engine, a connecting pipeextending substantially vertically adjacent to and between said intakepipes, and a connecting box disposed immediately beneath said fuel tankbetween said legs thereof, the upper ends of said air intake pipes alsobeing disposed between said legs of said fuel tank, said connecting boxinterconnecting said upper ends of said intake pipes and said connectingpipe.
 2. A combination according to claim 1 in which an air cleaner isdisposed between said intake pipes and connected to the lower end ofsaid connecting pipe.
 3. A combination according to claim 2 in which theinterior of said connecting box is so proportioned as to constitute anintake silencer.
 4. A combination according to claim 1 in which there isa said intake pipe for each said cylinder. .Iadd.
 5. In combination: amotorcycle frame; a multi-bank, multi-cylinder V-type engine supportedby said frame with its crankshaft extending transversely thereto, a fueltank supported by said frame, said fuel tank being disposed above saidengine and being generally V-shaped, with legs depending downwardly ateach side; and air intake conduitry comprising a respective air intakepipe extending upwardly from each bank of said engine, a connecting boxdefining an inner cavity positioned in proximity to the valley of saidV-type engine and contiguous to said fuel tank, said intake pipes allopening into the inner cavity of said connecting box, and an inletdevice providing the air inlet to said connecting box, said inlet devicebeing positioned in the area between said valley and said fuel tank andcomprising an outlet communicating with said connecting box, an inletand an air filter element interposed between said inlet and said outlet..Iaddend. .Iadd.6. A combination according to claim 5 wherein the inletdevice is positioned beneath the connecting box. .Iaddend. .Iadd.7. Acombination according to claim 5 wherein the connecting box ispositioned at least in part between the depending legs of the fuel tank..Iaddend.